KR20040014288A - Method for manufacturing highly- crystallized oxide powder - Google Patents

Abstract

PURPOSE: A method for producing high crystallinity multiple oxide powder of high dispersion which has no intrusion of impurities, and has a uniform grain size at a low cost and with simple equipment is provided. CONSTITUTION: The method for producing high crystallinity multiple oxide powder comprises the steps of injecting raw material powder including two or more kinds of metal elements and/or semimetal elements including multiple oxide in individual grains at fixed compositional ratios into a reaction vessel through a nozzle together with a carrier gas; and, in a state where the raw material powder is dispersed into a vapor phase at a concentration of less than or equal to 10 g/L, performing heating at a temperature higher than the decomposition temperature or reaction temperature thereof, and also, at a temperature satisfying (Tm/2) deg.C or higher provided that the melting point of the multiple oxide to be produced is defined as Tm/2 deg.C to produce the multiple oxide powder.

Description

Manufacturing method of high crystalline oxide powder {METHOD FOR MANUFACTURING HIGHLY- CRYSTALLIZED OXIDE POWDER}

The present invention relates to a metal oxide powder having high crystallinity, a semimetal oxide powder, or a method for producing a double oxide powder containing two or more metal elements and / or semimetal elements. In particular, functional materials for electronics such as phosphor materials, dielectric materials, magnetic materials, conductor materials, semiconductor materials, superconductor materials, piezoelectric materials, magnetic recording materials, anode materials for secondary batteries, electromagnetic wave absorbing materials and catalyst materials, and raw materials for their manufacture The present invention relates to a method of producing a highly dispersible high crystalline oxide powder having high purity and uniform particle size, which is useful as an industrial material used in various fields.

Powders of complex oxides containing metal oxides, semimetal oxides, and two or more metal elements and / or semimetal elements (hereinafter, referred to as "oxide powder") used as functional materials, function as In order to exert sufficiently, high purity, compositional uniformity and high crystallinity are required. In particular, in order to improve fluorescence properties such as light emission intensity, there are few impurities, there are no defects or lattice deformations on the surface and inside of the particles, they are compositionally homogeneous, and in particular, trace amounts of active elements are uniformly distributed. There is a need for a highly crystalline oxide powder consisting of a single crystalline phase.

In addition, even when the oxide powder is molded and heat treated by a sintering process to form a sintered body, it is important to control the characteristics of the oxide powder as a raw material. For example, in order to obtain a high performance oxide core or an oxide permanent magnet having excellent magnetic properties and mechanical strength, it is required that the oxide powder serving as a raw material be composed of fine particles having uniform particle size, isotropic shape and single crystal. do.

In addition, in the case where the oxide powder is dispersed in a matrix such as a resin and used as a thick film paste, ink, paint, sheet, green compact, or other composite material, in addition to the improvement of the original characteristics of the oxide, dispersibility, packing property, In order to improve workability, it is important that the particle shape and particle diameter are uniform and that the particles do not aggregate. In particular, for thick film pastes, it is preferable that they are fine monodisperse powders having no agglomeration and having a narrow particle size distribution and having an average particle diameter of about 0.1 to 10 m.

Conventionally, oxide powders have been prepared by solid-phase reaction, gas-phase reaction, liquid-phase reaction and spray pyrolysis.

In the solid phase reaction method, a mixture of raw powders such as oxalate, carbonate and oxide is placed in a baking vessel such as a crucible and heated at a high temperature for a long time to cause a solid phase reaction, which is ground by a ball mill or the like. However, the oxide powder produced by this method is composed of aggregates having irregular particle shapes and large particle size distribution. In addition, many impurities are mixed from the crucible or the grinding process. In addition, in the preparation of the complex oxide, a long time treatment is required at a high temperature in order to increase the homogeneity of the composition. As a result, the efficiency is bad. Moreover, the particle surface is deteriorated by physical impact and chemical reactions received during the grinding process, and many defects are generated on the particle surface and inside. As a result, a decrease in crystallinity and a decrease in physical properties originally possessed by the oxide are caused.

As a gas phase reaction method in which a vapor of a metal or metal compound is reacted in a gaseous phase, it is possible to produce a fine oxide powder. However, not only is it expensive, but the powder obtained is easy to aggregate, and it is difficult to control the particle diameter.

Examples of the liquid phase reaction method include those by liquid phase precipitation, hydrothermal methods, hydrolysis of inorganic salts and alkoxides, and the like. These methods yield oxide fine powders that are relatively free of surface modification and have high crystallinity. However, it is difficult to produce fine powder having no aggregation and high dispersibility. In addition, high-purity raw materials are required, and manufacturing costs are expensive, such as requiring a long time for reaction or separation operation.

Spray pyrolysis is a method of spraying a solution obtained by dissolving or dispersing a metal compound in water or an organic solvent to obtain fine droplets, and heating the droplets under the conditions in which metal oxides can be precipitated to produce metal oxide powder. to be. In this method, fine monodisperse particles without aggregation can be obtained, and impurities are also less mixed. Moreover, since a raw material is a solution, each metal component can be mixed uniformly at arbitrary ratios. Therefore, this method is considered to be suitable as a method for producing a complex oxide powder. For example, Japanese Patent Laid-Open No. 2001-152146 discloses producing a fine phosphor powder having excellent light emission characteristics by this method.

However, the spray pyrolysis method uses a large amount of organic solvents such as water, alcohol, acetone and ether in order to make the metal compound as a liquid droplet into a liquid. Therefore, enormous energy is required to evaporate the solvent, and the energy loss during pyrolysis is large, resulting in high cost. Moreover, due to decomposition of the solvent, it is difficult to control the atmosphere during thermal decomposition. Moreover, the particle size distribution of the produced | generated particle | grains may become large by the coalescence and division | segmentation of a droplet in a reaction container. For this reason, it is difficult to set reaction conditions such as spray rate, droplet concentration in the carrier gas, residence time in the reaction vessel, and poor productivity. Moreover, this method is limited to being capable of solution or suspension of starting materials. Therefore, the composition range and concentration of the raw material are limited, and the kind of oxide powder that can be produced is limited.

An object of the present invention is to produce a highly dispersible high crystalline oxide powder having no impurities mixed therein and having a uniform particle size in a low cost and simple process. In particular, it is an object of the present invention to provide a method for producing a functional oxide powder, such as a phosphor, for which homogeneity and high crystallinity of composition is strongly required, or an oxide powder suitable as a raw material for a functional ceramic or a functional composite material. Still another object is to obtain an oxide powder having a shape and particle size suitable for thick film paste such as phosphor paste, ink, paint, etc., and having a uniform particle size.

The gist of the present invention is as follows.

1. A raw material powder containing at least one element selected from the group consisting of metal elements and semimetal elements constituting the oxide is blown into the reaction vessel through a nozzle such as a carrier gas; When the raw powder is dispersed in the gas phase at a concentration of 10 g / L or less, when the melting point of the oxide that is higher than its decomposition temperature or reaction temperature and the produced oxide is Tm 占 폚 is (Tm / 2) 占 폚. It is heated to the above temperature, The manufacturing method of the high crystalline oxide powder characterized by the above-mentioned.

2. The condition according to the above 1, wherein when the raw material powder is ejected into the reaction vessel, the flow rate per unit time of the carrier gas is V (L / min) and the cross-sectional area of the opening of the nozzle is S (cm 2). V / S> 600 manufacturing method characterized in that.

3. The method according to the above 1 or 2, wherein the raw material powder is mixed and dispersed in the carrier gas using a disperser before the raw material powder is ejected into the reaction vessel through the nozzle.

4. The production method according to any one of 1 to 3, wherein the particle size of the raw material powder is adjusted in advance.

5. The oxide according to any one of the above items 1 to 4, wherein the raw material powder contains at least two elements selected from the group consisting of metal atoms and semimetal atoms in substantially uniform composition ratios in the individual particles of the raw material powder. Method for producing a complex oxide.

6. The particle according to any one of 1 to 5, wherein each particle constituting the raw material powder is at least two selected from the group consisting of metal elements and semimetal elements, or in the group consisting of metals, semimetals, and compounds thereof. A method of producing an alloy comprising at least two selected from the group consisting of an alloy comprising a composite comprising at least two selected or metal or semi-metal elements.

7. To prepare a raw material powder comprising at least two elements selected from the group consisting of metal elements and semimetal elements constituting the oxide in the material powders at substantially constant composition ratios;

Collecting the raw powder;

The collected raw powder is dispersed in a carrier gas using a disperser;

Spraying a carrier gas containing the dispersed raw powder into the reaction vessel through a nozzle;

When the raw material powder is dispersed in the gas phase at a concentration of 10 g / L or less, when the melting point of the complex oxide that is higher than its decomposition temperature or reaction temperature and the produced double oxide is (Tm / 2), (Tm / 2) A method for producing a highly crystalline oxide powder, comprising heating to a temperature of at least C to produce a complex oxide powder.

8. The condition for spraying the carrier gas containing the dispersed raw material powder into the reaction vessel according to the above 7, wherein the flow rate per unit time of the carrier gas is V (L / min), and the cross-sectional area of the opening of the nozzle is S. When (cm 2), V / S> 600, characterized in that the manufacturing method.

9. The production method according to 7 or 8 above, wherein the raw material powder is adjusted beforehand or after dispersing in the carrier gas using a grinder.

10. The group according to any one of items 7 to 9, wherein each particle constituting the raw material powder is composed of at least two elements selected from the group consisting of metal elements and semimetal elements, or metals, semimetals, and compounds thereof. A method of producing an alloy comprising at least two elements selected from the group consisting of an alloy comprising a composite comprising at least two selected from or a metal element and a semimetal element.

11. A highly crystalline oxide powder prepared by the method of any one of 1 to 10 above.

12. A highly crystalline phosphor oxide powder prepared by the method of any one of 1 to 10 above.

13. A phosphor composition comprising the highly crystalline phosphor oxide powder of 12 above.

14. A raw material powder containing at least one element selected from the group consisting of metal elements and semimetal elements constituting an oxide is supplied to a reaction vessel, such as a carrier gas; The raw material powder is dispersed in the gas phase at a concentration of 10 g / L or less, and is heated to a temperature higher than its decomposition temperature or reaction temperature and near or above the melting point of the oxide produced. Method for producing monocrystalline oxide powder.

15. A monocrystalline oxide powder prepared by the method of item 14 above.

[Embodiment of the Invention]

In the present invention, the metal element and semimetal element (hereinafter, referred to as "metal element") serving as components of the oxide powder are not particularly limited. For example, typical metal elements such as alkali metal, alkaline earth metal, Al, Ga, In, Sn, Tl, Pb, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo Transition metal elements such as Hf, Ta, W, Ag, Au, platinum group metals, and lanthanum rare earth metal elements such as Y, La, Ce, Gd, Eu, Tb, Sm, Pr, Yb, P, Si, B Elements such as semimetals such as, Ge, Sb, and Bi are usually selected to form an oxide.

According to the method of the present invention, various oxide powders such as metal oxide powder, semimetal oxide powder, and double oxide powder can be produced, and the type of oxide is not particularly limited. For example, Si0 ₂ , Al ₂ 0 ₃ , TiO ₂ , Fe ₃ 0 ₄ , Fe ₂ 0 ₃ , CoO, Co ₃ 0 ₄ , NiO, Cu ₂ 0, CuO, ZnO, Li ₂ O, BaO, Y ₂ 0 ₃ , La ₂ O ₃ , RuO ₂ , Ta ₂ 0 ₅ , Ce0 ₂ , SnO ₂ , In ₂ O _3, and the like. Hereafter, the complex oxide refers to at least two elements selected from metal elements and semimetal elements, and oxygen. For example, SrAl ₂ O ₄ : Eu, (Sr, Ca) B ₄ O ₇ : Eu, Y ₂ SiO ₅ : Ce, BaMgAl ₁₀ 0 ₁₇ : Eu, BaAl ₁₂ O ₁₉ : Mn, Y ₃ Al ₅ O ₁₂ : Ce, Y ₃ Al ₅ O ₁₂ : Tb, Zn ₂ Si0 ₄ : Mn, InBO ₃ : Tb, Y ₂ 0 ₃ : Eu, InBO ₃ : Eu, YVO ₄ : Eu, Mg ₂ SiO ₄ : Mn, Zn ₃ (PO ₄ ) ₂ : Mn, (Y, Gd) BO ₃ : Eu, (Y, Gd) BO ₃ : Tb, SrTiO ₃ : Eu, ZnO-LiGaO ₂ phosphor materials such as BaTiO ₃ , SrTiO ₃ , Pb ( Mg _1/3 Nb _2/3 ) Dielectric materials such as O ₃ , PZT, PLZT, piezoelectric materials, magnetic materials such as ferrite, conductor materials such as Pb ₂ Ru ₂ O ₆ , ITO, YBa ₂ Cu ₃ O _y, etc. Superconductor materials, such as LiMn ₂ O ₄ , Li ₃ V ₂ (PO ₄ ) ₃ , Li ₃ Fe ₂ (PO ₄ ) ₃ , LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , LaCoO ₃ , LaMnO ₃ Materials, electrode materials for solid electrolyte fuel cells such as La _1-x Sr _{x + y} CrO ₃ , photocatalyst materials such as BaTi ₄ O ₉ , Nb ₆ O ₁₇ , CuAlO ₂ , or photofunctional materials.

In the present invention, as a raw material powder, a powder containing at least one selected from the group consisting of metals, semimetals, metal compounds and semimetal compounds is prepared. Examples of powders of metals and semimetal compounds include hydroxides, nitrates, sulfates, oxynitrates, oxysulfates, halides, carbonates, borates, silicates, ammonium salts, ammonium complexes, phosphates, carbonates, resinates, sulfonates, acetylaceto Powders of inorganic or organic compounds such as nates, alkoxides, amide compounds, imide compounds and urea compounds are used. Suitable examples of semimetal element compounds such as boron, silicon, and phosphorus include boric acid, phosphoric acid and silicic acid.

In particular, in the preparation of the complex oxide powder, a powder containing a plurality of metal elements in a substantially constant composition ratio in each particle is used as the raw material powder. Examples thereof include a powder of a single compound containing at least two metal elements such as complex salt powder, multinuclear complex powder, alkoxide complex powder, alloy powder and glass powder. It is also possible to use coated complex particles or powders made of complex particles prepared before complexing a metal or metal compound. A composite powder or compound powder containing at least two kinds of elements can be obtained by the following method.

(1) Solid phase reaction method which mixes the metal or metal compound used as a raw material previously, heat-processes until it becomes uniform uniformly, and grind | pulverizes.

(2) An alkoxide method in which a plurality of metal alkoxides are reacted and co-condensed, then hydrolyzed and selectively heat treated to obtain a complex oxide precursor.

(3) A coprecipitation method wherein a precipitant selected from various precipitants is added to a solution containing a plurality of metal compounds to obtain a precipitate in which each component is uniformly mixed. For example, carbonate or oxalate is added to the metal nitrate solution for reaction, and the precipitate obtained is filtered and dried to obtain a complex of carbonate or oxalate. Alternatively, this is calcined to obtain an oxide complex.

(4) The urea homogeneous precipitation method, in which urea is added to a solution containing a plurality of metal compounds and heated to react to obtain uniform precipitation of hydroxides, carbonates and the like. The oxide precipitate may be obtained by further calcining the obtained precipitate.

(5) A complex polymerization method wherein a plurality of metal compounds, an aqueous solution of a mixture of carboxylic acids such as citric acid and a polyol such as ethylene glycol are heated to react to form a complex polymer of homogeneous metal complex.

(6) A spray pyrolysis method for obtaining a composite powder containing a plurality of metal elements in a substantially constant ratio by spray drying or spray pyrolyzing a solution or suspension containing a plurality of metal compounds uniformly.

In particular, the complex oxide precursor powder obtained by the alkoxide method, the complex oxide powder obtained by the precipitation method such as coprecipitation method or urea uniform precipitation method, the composite polymer powder of the metal complex obtained by the complex polymerization method, and the spray pyrolysis method obtained It is preferable to use a composite powder or the like as a raw material powder because it is easy to manufacture a highly crystalline double oxide powder that is extremely homogeneous in composition. The raw material powders prepared by these methods are once collected and then mixed with a carrier gas.

The flux component may be further introduced into the raw powder. The flux acts as a solvent in the gas phase reaction, but does not react with the target oxide, but increases the transport of the material by dissolving very small amounts, thereby increasing the reaction. Conventional fluxes such as alkali metal chlorides, alkaline earth metal chlorides, boric acid, borate salts such as sodium chloride, barium fluoride and the like are used for this purpose. These compounds are introduced into each particle of the raw powder or coated on the raw powder.

As a carrier gas, oxidizing gases, such as air, oxygen, and steam, an inert gas, such as nitrogen and argon, these mixed gases etc. are used normally. When it is necessary to make the atmosphere at the time of heat processing as a reducing component, reducing compounds, such as hydrogen, carbon monoxide, methane, and ammonia gas, or organic compounds, such as alcohols and carboxylic acids, which decompose upon heating and produce a reducing component crisis You may mix. In addition, when a metal compound (for example, a composite polymer of a metal complex obtained by a complex polymerization method, an alkoxide, a carboxylate) capable of generating carbon monoxide, methane or the like at the time of pyrolysis, is used as a raw material, It is also possible to provide a reducing component crisis without supplying a reducing gas to the reaction system from the outside.

In the case of producing a phosphor oxide powder that requires strict control of the valence of the activator ions or an oxide powder that requires controlled oxygen deficiency, in a spray pyrolysis method using a conventional aqueous solution, the interior of the furnace is formed by decomposition of water. Atmosphere becomes close to the oxidative atmosphere. Therefore, even if a reducing gas is introduced, it is difficult to control the atmosphere. For example, in the case of phosphors such as SrAl ₂ O ₄ : Eu ²⁺ , BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , Y ₂ SiO ₅ : Ce ³⁺ , etc. which use divalent Eu ions or trivalent Ce ions as activators, Very strong reducing component crisis is needed. Therefore, the production of the powder is difficult by spray pyrolysis. For this reason, the process has become complicated in the past, such as further heat-processing the produced powder in a hydrogen containing gas atmosphere. However, in the present invention, since a solvent such as water is not used, a strong reducing atmosphere can be easily created. This method is particularly suitable in the case where it is desired to strictly control the degree of oxidation of the oxide.

In the present invention, it is important that the solid raw material powder is ejected into the reaction vessel together with the carrier gas through the nozzle, and heat-treated in a state where the raw powder particles are highly dispersed in the gas phase. In other words, in the reaction vessel, the raw powder must be heat-treated in a state where the raw powder is dispersed at a low concentration so that the raw particles and the produced particles do not collide with each other. For this reason, the concentration in gaseous phase should be 10 g / L or less. If the concentration is higher than this, collisions between particles and sintering occur, and an oxide powder having a uniform particle size cannot be obtained. There is no restriction | limiting in particular if dispersion concentration is 10 g / L or less, It determines suitably according to the dispersion apparatus and heating apparatus to be used. However, if the concentration is too low, the production efficiency becomes worse. Therefore, it is preferable that dispersion concentration is 0.01 g / L or more.

In order to supply the individual raw material powder particles into the reaction vessel in a more reliably dispersed state, it is preferable to mix and disperse the raw material powder in the carrier gas using a disperser before ejecting the raw material powder into the reaction vessel through the nozzle. As a disperser, well-known airflow dispersers, such as an ejector type, a Venturi type, an orifice type, and a well-known airflow grinder are used.

More preferably, when the flow rate per unit time of the carrier gas is V (L / min) and the cross-sectional area of the opening of the nozzle is S (cm 2), the raw material powder is reacted at high speed under the condition that V / S> 600. Eject into a container. As a result, the raw material powder can be satisfactorily dispersed in the gas phase without reaggregation by rapid expansion of the gas in the reaction vessel. There is no restriction | limiting in particular in a nozzle, What kind of shape may be used, such as the cross section being circular, polygonal, or slit-shaped, the tip being shortened, and reducing to the middle and widening in an opening part.

In this method, since it heats in the state disperse | distributed highly in the gaseous phase, it is thought that 1 particle of oxide powder produces | generates per particle of a raw material powder. Therefore, the particle size of the oxide powder produced varies depending on the type of raw material powder, but is almost in proportion to the particle size of the raw material powder. Therefore, in order to obtain an oxide powder having a uniform particle diameter, one having a uniform particle size of the raw material powder is used. When the particle size distribution of the raw material powder is wide, it is preferable to preliminarily adjust the particle size by grinding, comminuting or classifying with a grinder or classifier. As the pulverizer, any of air flow crusher, wet crusher, and dry crusher may be used. The particle size may be adjusted before the raw material powder is dispersed in the carrier gas, but may also be dispersed at the same time as the dispersion using an air flow crusher or the like.

In order to heat-treat while maintaining the state which the raw material powder was disperse | distributed to low density | concentration, For example, using a tubular reaction container heated outside, the raw material powder is conveyed through a nozzle from one opening of the reaction container, Along with the gas is blown at a constant flow rate and passed through the reaction vessel. The oxide powder produced by the heat treatment is recovered at the other opening. The passage time of the mixture of the powder and the carrier gas in the reaction vessel is set according to the apparatus (or vessel) used so that the powder is sufficiently heated to a predetermined temperature. Usually, it is about 0.3 to 30 seconds. The heating may be performed outside of the reaction vessel by an electric furnace or a gas furnace, or the combustion gas may be supplied into the reaction vessel and the combustion salt may be used.

The heating is performed at a temperature higher than the decomposition temperature or the reaction temperature of the raw material powder under the production conditions of the oxide powder. In the heat treatment, when the melting point of the oxide powder is set to Tm 占 폚, it is necessary to set it to (Tm / 2) 占 폚 or more. If the heating temperature is lower than (Tm / 2) 占 폚, the target oxide powder cannot be obtained. In order to obtain an oxide powder with higher crystallinity, it is preferable to heat at a temperature equal to or higher than the sintering start temperature of the target oxide.

In the present invention, the raw material powder is heated at low concentration in the gas phase and highly uniformly dispersed by the high speed air stream from the nozzle. Therefore, it is estimated that even at high temperatures, the dispersed state can be maintained without agglomeration between particles by fusion and sintering, and a solid-phase reaction occurs within one particle at the same time as pyrolysis. Since it is a solid phase reaction in a limited region, crystal growth is accelerated in a short time, and the oxide powder which consists of primary particles with high crystallinity, few internal defects, and no aggregation can be obtained. In addition, especially in the case of the double oxide, since the elemental elements are contained in the individual raw material powder particles at a substantially constant composition ratio, the double oxide powder having an extremely homogeneous composition can be obtained.

In addition, when the raw material powder produces nitrides, carbides or the like during or after pyrolysis, heating is performed under the decomposition conditions.

When the flux component is added to the raw material powder, a high crystal oxide powder can be obtained under the same heating conditions due to the effect of the flux as a reaction enhancer. The flux component is removed by a conventional method of washing with water after producing an oxide powder.

The optimal heating temperature varies depending on the composition and use of the oxide powder, the required crystallinity, the shape of the particles, the heat resistance and the like. Therefore, heating temperature is suitably determined according to a desired characteristic. For example, it is preferable to set it as about 1200-1800 degreeC in an oxide fluorescent substance, and 900 degrees C or less in the battery electrode electrode material with low heat resistance.

When heated at a relatively low temperature, the particle shape of the resulting powder is generally the same as that of the raw powder. As the heating temperature increases, the automorphism of the crystal becomes apparent. In general, in order to obtain a highly crystalline or single crystal oxide powder having a uniform particle shape, it is preferable to heat it to a temperature near or above the melting point of the target oxide. For example, in order to obtain a highly crystalline spherical powder of ferrite, it is necessary to pyrolyze at least at 1200 ° C.

If desired, the obtained oxide powder may be further annealed. For example, in the case of a phosphor, annealing is performed at 400-1800 degreeC. By the annealing treatment, crystallinity is improved and the valence of the active agent is controlled to improve the emission intensity, to control the afterglow time and the emission color tone. The powder obtained in the present invention has high crystallinity of particles and maintains homogeneity of composition. Therefore, even when annealing at high temperature, aggregation of particles by sintering is unlikely to occur.

In the method of the present invention, it is possible to produce a highly crystalline oxide powder having an arbitrary average particle diameter and a narrow particle size distribution. Particularly, the phosphor powder used in phosphor compositions such as phosphor pastes, phosphor inks and phosphor green sheets can be prepared. Suitable for manufacture In order to manufacture the phosphor paste and the phosphor ink, the highly crystalline oxide phosphor powder produced by the method of the present invention is uniformly mixed and dispersed in an organic solution made of a resin, a solvent, or the like according to a conventional method. The phosphor green sheet is obtained by appropriately mixing a high crystalline oxide phosphor powder prepared by the method of the present invention with a resin and a solvent to obtain a slurry, and placing the slurry on the stretchable resin film by a method such as a doctor blade method. To dry. The phosphor composition or thick film paste may contain inorganic binders such as glass particles, pigments and other additives.

EXAMPLE

Next, an Example and a comparative example demonstrate this invention concretely.

(Y ₂ O ₃ : Eu ³⁺ phosphor powder)

Example 1

The yttrium nitrate hexahydrate and the europium nitrate hexahydrate were weighed so that the europium nitrate hexahydrate was 4 mo1% relative to the yttrium nitrate hexahydrate, dissolved in pure water, and an aqueous solution having a total metal ion concentration of about 0.1 mo1 / L was prepared. Produced. To this solution, an aqueous ammonium carbonate solution was added at normal temperature to co-precipitate yttrium and europium. The precipitate thus produced was collected by filtration, dried at 100 ° C., and pulverized with an air flow crusher to obtain a carbonate composite powder having a uniform particle size with an average particle diameter of about 2 μm.

The powder obtained was blown into a reaction tube heated at 1550 ° C. by an electric furnace through a nozzle having a cross-sectional area of 0.13 cm 2 at an opening rate of 5 kg / hr with air having a flow rate of 200 L / min as a carrier gas. The reaction tube was passed through heating while maintaining the dispersion concentration of. The dispersion concentration of the raw material powder in the gas phase in the reaction tube was 0.4 g / L and V / S = 1500. The resulting white powder was collected by a bag filter.

The powder obtained was analyzed by X-ray diffractometer and found to be a complex oxide powder composed of a single crystal phase represented by (Y _0.96 Eu _0.4 ) ₂ O ₃ and having extremely good crystallinity. Furthermore, when observed with a scanning electron microscope (SEM), it was a powder with a narrow particle size distribution of 1 micrometer of average particle diameters and 3 micrometers of maximum particle diameters which consist of a spherical particle shape without aggregation. Furthermore, when the emission spectrum of wavelength 612nm was measured under the ultraviolet irradiation of wavelength 147nm, the emission intensity was 150% of the emission intensity of the powder whose average particle diameter obtained by the conventional solid-state reaction method is 3 micrometers.

Example 2

A carbonate composite powder having an average particle diameter of about 2 µm prepared in the same manner as in Example 1 was mixed with an air carrier gas using an ejector-type disperser. The obtained solid-gas mixture was blown into a reaction tube heated to 1550 ° C. by an electric furnace through a nozzle having a flow rate of 200 L / min and a cross-sectional area of 0.13 cm 2 of the opening, and heated through a reaction tube. The feed rate of the powder, the raw material powder dispersion concentration in the gas phase in the reaction tube, and V / S were 5 kg / hr, 0.4 g / L and 1500, respectively as in Example 1.

The obtained powder was confirmed to be (Y _0.96 Eu _0.4 ) ₂ O ₃ powder having extremely high crystallinity by X-ray diffraction analysis. As a result of SEM observation, it was composed of spherical particles without aggregation, and had an average particle diameter of 0.8 µm and a maximum particle diameter of 2 µm, which were smaller in particle size and narrower in particle size distribution than those of the particles of Example 1 without using a disperser. The emission intensity at the wavelength of 612 nm under ultraviolet irradiation at the wavelength of 147 nm was about the same as in Example 1.

Examples 3 and 4

A double oxide powder was prepared in the same manner as in Example 1 except that the temperature of the electric furnace was 1450 ° C and 1650 ° C, respectively. The properties of the powder obtained are shown in Table 1.

In addition, the emission intensity shown in the table is the emission intensity at wavelength 612 nm under ultraviolet irradiation at wavelength 147 nm, and the emission intensity of (Y _0.96 Eu _0.4 ) ₂ O ₃ powder having an average particle diameter of 3 μm obtained by the conventional solid state reaction method is 100. Relative strength when In addition, the crystallinity is shown by the relative strength when the X-ray diffraction intensity of the powder of Example 1 is 100.

Example 5

The same procedure as in Example 1 was carried out except that the feed rate of the raw material powder was 1.25 kg / hr. The dispersion concentration of raw material powder in the gas phase is 0.1 g / L. The properties of the powder obtained are shown in Table 1.

Example 6

The feed rate of the raw material powder was 62.5 kg / hr, and the same procedure as in Example 1 was carried out except that the average particle diameter of the raw material powder was 4 µm. The dispersion concentration of the raw material powder in the gas phase is 5.0 g / L. The properties of the powder obtained are shown in Table 1.

Example 7

A double oxide powder was prepared in the same manner as in Example 1 except that the cross-sectional area of the opening of the nozzle was 0.03 cm 2. The properties of the powder obtained are shown in Table 1.

Example 8

A composite oxide powder was prepared in the same manner as in Example 1 except that the cross-sectional area of the opening of the nozzle was 0.28 cm 2. The properties of the powder obtained are shown in Table 1.

Example 9

A double oxide powder was produced in the same manner as in Example 1 except that the cross-sectional area of the opening of the nozzle was 0.5 cm 2. Crystallinity and luminescence properties of the obtained powder were good, but when observed by SEM, a large amount of large amorphous particles was confirmed.

Example 10

The yttrium nitrate hexahydrate and europium nitrate hexahydrate were weighed so that the europium nitrate hexahydrate was 4 mo1% relative to the yttrium nitrate hexahydrate, and dissolved in pure water to prepare an aqueous solution having a total metal ion concentration of about 0.1 mol / L. The solution was treated with an ultrasonic nebulizer to obtain fine droplets, and spray pyrolysis was carried out at 70 ° C. using air as a carrier gas. Collected with a bag filter, Y ₂ O ₃ -EuO composite powder having an average particle diameter of about 2㎛. The Y ₂ O ₃ -EuO composite powder was pulverized with an air flow crusher to obtain an average particle diameter of about 0.5 mu m, and then mixed with an air carrier using an orifice type disperser. The obtained solid-gas mixture was blown into a reaction tube heated at 1550 ° C. by an electric furnace through a nozzle having a cross-sectional area of 0.13 cm 2 at an opening at a flow rate of 200 L / min as in Example 2, and heated through a reaction tube. The feed rate of the powder, the dispersion concentration of the raw material powder in the gas phase in the reaction tube, and the V / S are 5 kg / hr, 0.4 g / L and 1500, respectively.

The obtained powder was a spherical powder of (Y _0.96 Eu _0.4 ) ₂ O ₃ having extremely high crystallinity. Powder characteristics are shown in Table 1.

Comparative Example 1

The same procedure as in Example 1 was carried out except that the feed rate of the raw material powder was 150 kg / hr. The powder concentration in the gas phase in the reaction tube was 12.0 g / L. When the obtained powder was observed by SEM, a plurality of particles were fused to form huge amorphous particles, and the particle size distribution was wide. The properties of the powder are shown in Table 1.

Comparative Example 2

It carried out like Example 1 except having set the temperature of an electric furnace to 1100 degreeC. This heating temperature is a temperature lower than 1/2 of the melting point (about 2300 ° C.) of (Y _0.96 Eu _0.4 ) ₂ O ₃ . The powder obtained was square columnar particles and had low crystallinity. Luminous intensity was also low. Powder characteristics are shown in Table 1.

Meteorological raw material powder concentration (g / L) Nozzle cross section area S (cm2) V / S Heating temperature (℃) Average Particle Diameter of Raw Material Powder (㎛) Characteristics of Produced Powder Average particle diameter (㎛) Particle size (㎛) Luminous intensity Crystallinity Example 1 0.4 0.13 1500 1550 2 One 3 150 100 Example 3 0.4 0.13 1500 1450 2 One 3 100 90 Example 4 0.4 0.13 1500 1650 2 One 3 150 98 Example 5 0.1 0.13 1500 1550 2 0.7 1.5 150 100 Example 6 5.0 0.13 1500 1550 4 3 8 150 98 Example 7 0.4 0.03 6700 1550 2 0.7 1.5 150 100 Example 8 0.4 0.28 710 1550 2 One 4 150 100 Example 9 0.4 0.50 400 1550 2 1.5 8 150 100 Example 10 0.4 0.13 1500 1550 0.5 0.5 One 150 100 Comparative Example 1 12.0 0.13 1500 1550 2 5 30 130 90 Comparative Example 2 0.4 0.13 1500 1100 2 One 3 10 30

(BaMgAl ₁₀ O ₁₇ : Eu ²⁺ phosphor)

Example 11

Barium nitrate, europium nitrate hexahydrate, magnesium nitrate hexahydrate, and aluminum nitrate hexahydrate were each weighed in a molar ratio of Ba: Eu: Mg: Al = 0.9: 0.1: 1: 10 and dissolved in pure water. Citric acid was dissolved by adding 1.5 times the mole of the total metal ions, and the same mole of ethylene glycol as citric acid was added. The solution was heated at 150 ° C. under stirring to obtain a gel polymer. The polymer was heated at 400 deg. C to remove the binder component and pulverized with an air flow crusher to obtain a raw material powder having a uniform particle size of about 2 mu m.

The powder thus obtained was blown into a reaction tube heated at 1600 ° C. in an electric furnace at a feed rate of 5 kg / hr through a nozzle having a flow rate of 200 L / min and 1% hydrogen-containing nitrogen at a cross-sectional area of 0.13 cm 2 as a carrier gas. The mixture was heated and passed through a reaction tube while maintaining the dispersion concentration of the powder. The dispersion concentration of raw material powder in the gas phase in the reaction tube was 0.4 g / L and V / S = 1500. The resulting powder was collected by a bag filter.

When the obtained powder was analyzed by X-ray diffractometer, only diffraction lines of Ba _0.9 Eu _0.1 MgAl ₁₀ O ₁₇ were confirmed. In observation by SEM, the particle size of about 1 micrometer of average particle diameters, and about 4 micrometers of maximum particle diameters was uniform, and was plate-shaped particle | grains. In addition, when the emission spectrum of wavelength 450nm was measured under the ultraviolet irradiation of wavelength 147nm, the emission intensity was the same as the emission intensity of the powder of average particle diameter 4micrometer obtained by the conventional solid-state reaction method.

(BaFe ₁₂ O ₁₉ Ferrite)

Example 12

Barium nitrate and ferric nitrate hydrate were weighed to a molar ratio of 1:12 and dissolved in pure water to prepare a solution having a total metal ion concentration of about 0.2 mol / L. The solution was heated to 80 ° C., and 2 mol / L concentration of urea was added while stirring to initiate a homogeneous precipitation reaction by hydrolysis of urea. The reaction was terminated by cooling when the pH of the solution reached 8. The resulting precipitate was filtered off, dried at 100 ° C. and calcined at 600 ° C. Subsequently, the resultant was pulverized with an air flow grinder to obtain a raw material powder having a uniform particle size of about 2 µm.

The raw material powder was blown into a reaction tube heated at 1300 DEG C with an electric furnace at a feed rate of 5 kg / hr through a nozzle having a flow rate of 200 L / min as a carrier gas, through a nozzle having a cross-sectional area of 0.13 cm 2. The reaction tube was passed through and heated while maintaining the dispersion concentration of. The dispersion concentration of the raw material powder in the gas phase in the reaction tube was 0.4 g / L and V / S = 1500. The resulting powder was collected by a bag filter. It was confirmed by SEM that the obtained powder was a plate-shaped particle with a narrow particle size distribution having an average particle diameter of about 1 μm and a maximum particle diameter of about 3 μm. In the analysis by X-ray diffractometer, only a sharp diffraction line of BaFe ₁₂ O ₁₉ was found.

(BaTiO ₃ Dielectric)

Example 13

Equimolar barium chloride hydrate and titanium chloride were dissolved in pure water to prepare a solution having a total metal ion concentration of 0.1 mol / L. This solution was added dropwise to an aqueous 0.5 mol / L oxalic acid solution to generate a precipitate of titanyl barium oxalate. The precipitate was filtered, washed with water, calcined at 500 ° C, wet milled with a bead mill using a 0.3 mm diameter zirconia ball, and dried to obtain a raw material powder. The raw material powder was subdivided and dispersed by air flow crusher using air having a flow rate of 200 L / min and immediately heated at 1100 ° C. by an electric furnace at a feed rate of 5 kg / hr through a nozzle having a cross-sectional area of 0.13 cm 2. Was ejected to. The dispersion concentration of raw material powder in the gas phase in the reaction tube was 0.4 g / L and V / S = 1500. The raw material powder was heated through a reaction tube while maintaining the dispersion concentration of the powder. The resulting powder was collected with a bag filter. It was confirmed by SEM that the obtained powder was a particle | grains without aggregation of an average particle diameter of about 0.2 micrometer, and a maximum particle diameter of 0.4 micrometer. Analysis by X-ray diffraction system revealed only sharp diffraction lines of tetragonal BaTiO ₃ .

(ZnO powder)

Example 14

A commercially available high purity zinc oxide powder was ground with an air flow crusher to obtain a powder having a uniform particle size with an average particle diameter of about 2 µm. The powder was blown into a reaction tube heated at 1200 ° C in an electric furnace through a nozzle having a cross-sectional area of 0.13 cm 2 at an opening rate of 5 kg / km, with air having a flow rate of 200 L / min as a carrier gas. The reaction tube was heated while maintaining the dispersion concentration. The dispersion concentration of raw material powder in the gas phase in the reaction tube was 0.4 g / L and V / S = 1500. The produced white powder was collected by a bag filter.

The obtained powder was analyzed by X-ray diffractometer, and found to be a single crystal phase of ZnO, which was an oxide powder having extremely high crystallinity. When observed with a scanning electron microscope (SEM), it was confirmed that the powder had no aggregation, was almost spherical, and had a narrow particle size distribution having an average particle diameter of 2 µm and a maximum particle diameter of 5 µm.

Examples 15-18

An oxide powder was produced in the same manner as in Example 14 except that the raw material powder dispersion concentration in the gas phase, the cross-sectional area of the opening of the nozzle, and the temperature of the electric furnace were shown in Table 2, respectively. The properties of the obtained powder are shown in Table 2. Crystallinity is the relative strength when the X-ray diffraction intensity of the powder of Example 14 is 100.

Comparative Example 3

The same procedure as in Example 14 was carried out except that the feed rate of the raw material powder was 150 kg / hr. The powder concentration in the gas phase in the reaction tube was 12.0 g / L. As a result of observing the obtained powder by SEM, a plurality of particles were fused to form huge amorphous particles, and the particle size distribution was wide. The properties of the powder are shown in Table 2.

Comparative Example 4

It carried out like Example 14 except having set the temperature of an electric furnace to 800 degreeC. This heating temperature is a temperature lower than 1/2 of about 2000 degreeC (under pressure) which is a melting point of zinc oxide. The obtained powder was amorphous and had low crystallinity. Powder characteristics are shown in Table 2.

Type of oxide Meteorological concentration of raw material powder (g / L) Nozzle cross section area S (cm2) V / S Heating temperature (℃) Characteristics of Produced Powder Average particle diameter (㎛) Particle size (㎛) Crystallinity Example 14 ZnO 0.4 0.13 1500 1200 2 5 100 Example 15 ZnO 0.1 0.13 1500 1200 1.5 3 100 Example 16 ZnO 5.0 0.13 1500 1200 3 8 100 Example 17 ZnO 0.4 0.03 6700 1200 1.5 4 100 Example 18 ZnO 0.4 0.28 710 1200 2 6 100 Example 19 ZnO 0.4 0.50 400 1200 3 12 100 Comparative Example 3 ZnO 12.0 0.13 1500 1200 8 40 90 Comparative Example 4 ZnO 0.4 0.13 1500 800 2 6 70

Example 19

Commercially available zinc carbonate powder was pulverized with an air flow crusher to obtain a raw powder having an average particle diameter of about 0.2 탆. The powder was mixed with the air carrier gas using an ejector-type disperser at a feed rate of 1.25 kg / hr, and the obtained solid-gas mixture was flown through an nozzle at a flow rate of 200 L / min through a nozzle having a cross-sectional area of 0.13 cm 2 of the opening. Was blown into a reaction tube heated to 1200 ° C., and heated through a reaction tube. The dispersion concentration of the raw material powder in the gas phase in the reaction tube was 0.1 g / L and V / S = 1500. The resulting white powder was collected with a bag filter.

The obtained powder was confirmed to be ZnO powder having good crystallinity by X-ray diffraction analysis. As a result of SEM observation, it consisted of spherical particle | grains without aggregation, and the average particle diameter was 0.2 micrometer and the maximum particle diameter was 0.8 micrometer.

(CeO ₂ powder)

Example 20

An aqueous solution of ammonium oxalate was added to the aqueous solution of cerium chloride while stirring, and the precipitated cerium oxalate was filtered and dried to prepare a cerium oxalate powder. The powder was pulverized with an air flow crusher to obtain a raw material powder having an average particle diameter of about 1 탆. The powder was blown into a reaction tube heated at 1500 ° C. by an electric furnace through a nozzle having a cross-sectional area of 0.13 cm 2 at an opening rate of 5 kg / hr, accompanied by air having a flow rate of 200 L / min as a carrier gas. The reaction tube was heated while maintaining a dispersion concentration of. The melting point of cerium oxide is about 1950 ° C. The dispersion concentration of raw material powder in the gas phase in the reaction tube was 0.4 g / L and V / S = 1500. The resulting pale yellow powder was collected by a bag filter.

The obtained powder was confirmed to be Ce0 ₂ powder having good crystallinity by X-ray diffraction analysis. As a result of SEM observation, it consisted of spherical particle | grains without aggregation, and the average particle diameter was 0.8 micrometer and the maximum particle diameter was 2 micrometer.

(TiO ₂ Powder)

Example 21

The hydrous titanium oxide produced by hydrolysis of titanium sulfate was pulverized and dispersed by an air-flow pulverizer using air at a flow rate of 200 L / min, and immediately heated to 1400 ° C. by an electric furnace through a nozzle having a cross-sectional area of 0.13 cm 2 in the opening. The resultant was blown into a reaction tube, and then heated through a reaction tube while maintaining the dispersion concentration of the powder. The melting point of titanium oxide is about 1850 占 폚. The dispersion concentration of raw material powder in the gas phase in the reaction tube was 0.4 g / L and V / S = 1500. The resulting white powder was collected with a bag filter.

The obtained powder was confirmed to be rutile TiO ₂ powder having good crystallinity by X-ray diffraction analysis. As a result of SEM observation, it consisted of spherical particle | grains without aggregation, the average particle diameter was 2 micrometers, and the maximum particle diameter was 5 micrometers.

(Cobalt Oxide Powder)

Example 22

Commercial basic cobalt carbonate was pulverized with an air flow crusher to obtain a raw material powder having an average particle diameter of 1 탆. This powder was mixed with an air carrier using an ejector-type disperser at a feed rate of 5 kg / hr, and the obtained solid-gas mixture was 1500 ° C. in an electric furnace through a nozzle having a flow rate of 200 L / min and a cross section of an opening of 0.13 cm 2. The resultant was blown into a reaction tube heated by heating, and heated through a reaction tube while maintaining a powder dispersion concentration. The melting point of cobalt oxide is about 1935 ° C. The dispersion concentration of raw material powder in the gas phase in the reaction tube was 0.4 g / L and V / S = 1500. The resulting black gray powder was collected by a bag filter.

The obtained powder was confirmed to be a good crystallinity in which CoO and Co ₃ O ₄ were mixed by X-ray diffraction analysis. As a result of SEM observation, it consisted of spherical particle | grains without aggregation, and the average particle diameter was 0.7 micrometer, and the maximum particle diameter was 1.5 micrometer.

According to the present invention, an oxide powder composed of primary particles having a uniform composition, high crystallinity, high dispersibility, and no uniform particle-shaped aggregation can be easily obtained. In addition, since no additives or solvents affecting the purity are used, high-purity powders containing few impurities can be obtained. In addition, since no pulverization treatment is required, there are few defects or deformations on the particle surface and inside.

Further, in the present method, by controlling the particle size and dispersion conditions of the raw material powder, an oxide powder having a uniform particle diameter with an arbitrary average particle diameter can be obtained, from 0.1 μm or less to about 20 μm. This method is particularly suitable for producing fine powder having a narrow particle size distribution which is used as a thick film paste material. In addition, the powder is suitable as various functional materials or raw materials thereof, and also as a sintered raw material or a composite material.

In addition, since the raw material is not in the form of a solution or a suspension, energy loss due to evaporation of the solvent is small compared with a conventional spray pyrolysis method, and can be easily manufactured at low cost. Moreover, since there is no problem of unity of droplets and it can disperse | distribute in a gaseous phase with comparatively high concentration compared with the spray pyrolysis method, efficiency is high. In addition, since the raw material does not need to be liquefied or suspended, the selection range of the raw material is wide. Therefore, many kinds of oxide powders can be produced.

In addition, the method is free of oxidizing gas from the solvent. Therefore, it is also suitable for the preparation of complex oxide powder which needs to be synthesized under low oxygen partial pressure. Furthermore, by appropriate selection of raw material compounds, the system can be made into a reducing atmosphere during decomposition. In this case, it is not necessary to supply the reducing gas from the outside, and oxidation is suppressed. Therefore, setting of reaction conditions is simple.

In particular, the oxide phosphor prepared by the present method is compositionally homogeneous, and a small amount of activator ions are uniformly dispersed, and is highly crystalline without defects or lattice deformation on the surface and inside. Such powders are extremely excellent in phosphor characteristics such as luminous intensity. Furthermore, since the particles are fine monodispersed particles having a uniform particle shape and particle diameter, a phosphor paste having excellent dispersibility can be produced, and the powder filling density at the time of applying the paste is high, and the thin film can be formed.

Claims (18)

A raw material powder containing at least one element selected from the group consisting of metal elements and semimetal elements constituting the oxide is blown into the reaction vessel through a nozzle such as a carrier gas; When the raw powder is dispersed in the gas phase at a concentration of 10 g / L or less, when the melting point of the oxide that is higher than its decomposition temperature or reaction temperature and the produced oxide is Tm 占 폚 is (Tm / 2) 占 폚. It is heated to the above temperature, The manufacturing method of the high crystalline oxide powder characterized by the above-mentioned. 2. A condition according to claim 1, wherein the conditions for ejecting the raw material powder into the reaction vessel include V (L / min) for the flow rate per unit time of the carrier gas and S (cm 2) for the cross-sectional area of the opening of the nozzle. / S> 600 manufacturing method characterized in that. The method according to claim 1, wherein the raw material powder is mixed and dispersed in a carrier gas using a disperser before the raw material powder is ejected into the reaction vessel through a nozzle. The production method according to claim 1, wherein the particle size of the raw material powder is adjusted in advance. The method of claim 1, wherein the raw material powder comprises at least two elements selected from the group consisting of metal atoms and semi-metal atoms in a substantially constant composition ratio in each particle of the raw material powder, wherein the oxide produced is a complex oxide. Manufacturing method. 6. The particle of claim 5, wherein each particle constituting the raw material powder contains at least two elements selected from the group consisting of metal elements and semimetal elements, or at least two kinds selected from the group consisting of metals, semimetals, and compounds thereof. Or a single compound comprising at least two elements selected from the group consisting of a metal element and a semimetal element. Preparing a raw material powder comprising at least two elements selected from the group consisting of metal elements and semimetal elements constituting an oxide in the raw material powders at substantially constant composition ratios; Collecting the raw powder; The collected raw powder is dispersed in a carrier gas using a disperser; Spraying a carrier gas containing the dispersed raw powder into the reaction vessel through a nozzle; When the raw material powder is dispersed in the gas phase at a concentration of 10 g / L or less, when the melting point of the complex oxide that is higher than its decomposition temperature or reaction temperature and the produced double oxide is (Tm / 2), (Tm / 2) A method for producing a highly crystalline oxide powder, comprising heating to a temperature of at least C to produce a complex oxide powder. 8. The condition of ejecting the carrier gas containing the dispersed raw material powder into the reaction vessel according to claim 7, wherein the flow rate per unit time of the carrier gas is V (L / min) and the cross-sectional area of the opening of the nozzle is S ( Cm 2), the manufacturing method characterized in that V / S> 600. 8. The manufacturing method according to claim 7, wherein the raw material powder is preliminarily adjusted before or after the dispersion in the carrier gas by using a grinder. 8. The method of claim 7, wherein each particle constituting the raw material powder comprises at least two elements selected from the group consisting of metal elements and semimetal elements, or at least two kinds selected from the group consisting of metals, semimetals, and compounds thereof. Or a single compound comprising at least two elements selected from the group consisting of a metal element and a semimetal element. A highly crystalline oxide powder prepared by the method of claim 1. A highly crystalline oxide powder prepared by the method of claim 7. A highly crystalline phosphor oxide powder prepared by the method of claim 1. A highly crystalline phosphor oxide powder prepared by the method of claim 7. A phosphor composition comprising the highly crystalline phosphor oxide powder of claim 13. A phosphor composition comprising the highly crystalline phosphor oxide powder of claim 14. Supplying a raw material powder containing at least one element selected from the group consisting of metal elements and semimetal elements constituting an oxide to the reaction vessel, such as a carrier gas; The raw material powder is dispersed in the gas phase at a concentration of 10 g / L or less, and is heated to a temperature higher than its decomposition temperature or reaction temperature and near or above the melting point of the oxide produced. Method for producing monocrystalline oxide powder. Monocrystalline oxide powder prepared by the method of claim 17.